There’s lots of research on the matter, but of varying quality. This paper for example, measures the effectiveness of personalized ads in a sportswear website. Data found was nuanced, but the tldr is that personalized ads did, on the whole, increase the likelyhood a costumer would go further into the purchasing pipeline, but would be less effective over time with repeated exposure to the ads. Mind you, this paper didn’t measure personalized ads to confirmed sales, only ads to clicks (at least, that’s what I got from the discussion chapter, migraine’s kicking my ass rn).

There’s other papers related to the topic, but a bunch I found were qualitative and thus not the most reliable imo when measuring the effectiveness of advertisement imo.

Disclaimer: not a scientist, but had to take some related classes for my graphic design degree.